Few things have revolutionized the diagnosis of acute coronary syndrome as much as point-of-care troponin testing. The protein, released by cardiac muscle after a heart attack or other cardiovascular injury, enables faster, more accurate diagnoses (or rule-outs) of myocardial infarction (MI).

Our understanding of troponin is expanding, thanks to the use of high-sensitivity (hs-cTn) assays, now under investigation in the U.S. and available for clinical use in Europe and elsewhere. They show that even healthy people have baseline troponin levels, data that provides ever-greater importance to the proper use of troponin cutoff and change over time (delta change) to diagnose MI.

In Cardiac Troponin: Rule-Out and Rule-In Strategies and Use in Chronic Disease, a Morning Symposium at the 68th AACC Annual Scientific Meeting & Clinical Lab Expo, three experts highlight the most up-to-date research and techniques involving troponin assays. Fred Apple, PhD, of Hennepin County Medical Center, provides the clinical laboratory professional prospective; Judd Hollander, MD, of Thomas Jefferson University, discusses the emergency medicine perspective; and Allan Jaffe, MD, of the Mayo Clinic, delivers the cardiologist perspective.

Apple told CLN Stat that he plans to address analytical issues pertaining to improved imprecision at the sex-derived 99th percentiles for hs-cTn assays, particularly how these assays can eliminate imprecision noise. He will also highlight research demonstrating that hs-cTn assays won’t result in a substantially greater number of MIs, or myocardial injury diagnoses.

However, hs-cTn assays will improve emergency department flow and triage, said Jaffe. In addition, the availability of hs-cTn assays will expand the use of troponin as a marker for chronic diseases, whether hypertension or heart failure. “There are numerous clinical applications in the chronic disease state that are going to be extremely helpful when high sensitivity testing becomes available in the U.S.,” he explained.

In addition, Apple added, the new assays should provide a substantial costs savings in emergency departments.

Although the Food and Drug Administration (FDA) is still reviewing the data around hs-cTn assays, Apple and Jaffe stressed the need for U.S.-based laboratorians and clinicians to educate themselves on the analytical and clinical benefits for patient care, as well as provide earlier rule-out/rule-in for MI diagnoses.

“They need to read the peer-reviewed literature and share this information with their clinical colleagues,” Apple said. He also called for clinical laboratory professionals to lobby their congressional members and the FDA regarding the excessive time the agency is taking to approve the tests in the U.S.

“The U.S. is one to two years behind the rest of the world,” he said.